Fairly cheap..........$239 plus the cost of your MMPI????? (crazy test, can't remember the acronym). PI classes are hard to fill I've hear, same price IIRC.
https://www.autrytech.edu/CourseDetail/tabid/123/CourseId/605/Default.aspx
Just browsed my local votech. No courses offered. Dammit! I want to be a gumshoe.